Feature Flags API

Get the Set User Roles feature flag

GET /v2/config/feature_flags/set_roles_by_username

When enabled, Org Managers or Space Managers can add access roles by username.
In order for this feature to be enabled the CF operator must:
1) Enable the `/ids/users/` endpoint for UAA
2) Create a UAA `cloud_controller_username_lookup` client with the `scim.userids`
authority